Method of manufacturing light emitting device

ABSTRACT

The method of manufacturing a light emitting device includes: providing a light-transmissive member; providing light emitting elements each having a primary light emission surface and an electrode formation surface; bonding the light emitting elements to a base member such that the electrode formation surfaces face an upper surface of the base member; disposing a generally flat layer of a light-transmissive bonding member on an upper surface of the light-transmissive member; disposing the light emitting elements on the light-transmissive member such that the primary light emission surfaces face the upper surface of the light-transmissive member via the bonding member; disposing a part of the bonding member on a lateral surface of each of the light emitting elements; removing a part of the light-transmissive member to form a groove between the light emitting elements; forming a light-reflective member at least in the groove; and cutting the light-reflective member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 16/037,763 filed on Jul. 17, 2018. This application claimspriority to Japanese Patent Application No. 2017-146627, filed on Jul.28, 2017. The entire disclosures of U.S. patent application Ser. No.16/037,763 and Japanese Patent Application No. 2017-146627 are herebyincorporated by reference.

BACKGROUND

The present disclosure relates to a method of manufacturing a lightemitting device.

A light emitting device in which a light emitting element is mounted hasbeen used for a backlight of a liquid crystal display device, or thelike. In such a light emitting device, a light-transmissive membercontaining a fluorescent material is bonded onto a light emittingelement by a light-transmissive bonding member. It has been suggested toemploy a bonding member having a circular-arc shape at a lateral surfaceof a light emitting element for improving light extraction efficiency ona lateral side of such a light emitting device (Japanese UnexaminedPatent Publication 2013-12545).

SUMMARY

An object of the present disclosure is to provide a method ofmanufacturing a light emitting device, in which a light-transmissivemember can be efficiently disposed on a light emitting element moreeasily at an appropriate position and in an appropriate shape.

A method of manufacturing a light emitting device according to thepresent disclosure includes: providing a light-transmissive memberhaving a plate-like shape; providing a plurality of light emittingelements each having a primary light emission surface and an electrodeformation surface on a side opposite to the primary light emissionsurface; bonding the light emitting elements to an upper surface of abase member such that the electrode formation surface of each of thelight emitting elements faces the upper surface of the base member;disposing a generally flat layer of a light-transmissive bonding memberon an upper surface of the light-transmissive member; disposing thelight emitting elements on the upper surface of the light-transmissivemember such that the primary light emission surface of each of the lightemitting elements faces the upper surface of the light-transmissivemember via the bonding member interposed therebetween; disposing a partof the bonding member on a lateral surface of each of the light emittingelements; removing a part of the light-transmissive member to form agroove between the light emitting elements; forming a light-reflectivemember at least in the groove; and cutting the light-reflective memberand the base member.

According to the present disclosure, it is possible to provide a methodof manufacturing a light emitting device, in which a light-transmissivemember can be efficiently disposed on a light emitting element moreeasily at an appropriate position and in an appropriate shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic sectional diagram showing a process of a firstembodiment of a method of manufacturing a light emitting device.

FIG. 1B is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1C is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1D is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1E is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1F is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1G is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1H is a schematic sectional diagram showing a process of the firstembodiment of a method of manufacturing a light emitting device.

FIG. 1I is a schematic sectional view of a light emitting deviceobtained by the method of manufacturing a light emitting deviceaccording to the first embodiment.

FIG. 2 is a schematic sectional diagram showing one example of a methodof disposing a bonding member on a light-transmissive member.

FIG. 3 is a schematic sectional diagram showing a process of a secondembodiment of a method of manufacturing a light emitting device.

FIG. 4A is a schematic sectional diagram showing a process of a thirdembodiment of a method of manufacturing a light emitting device.

FIG. 4B is a schematic sectional diagram showing a process of the thirdembodiment of a method of manufacturing a light emitting device.

FIG. 4C is a schematic sectional diagram showing a process of the thirdembodiment of a method of manufacturing a light emitting device.

FIG. 4D is a schematic sectional diagram showing a process of the thirdembodiment of a method of manufacturing a light emitting device.

FIG. 5A is a schematic sectional diagram showing a process of a fourthembodiment of a method of manufacturing a light emitting device.

FIG. 5B is a schematic sectional diagram showing a process of the fourthembodiment of a method of manufacturing a light emitting device.

FIG. 6A is a schematic sectional diagram showing a modification of thefirst embodiment of a method of manufacturing a light emitting device.

FIG. 6B is a schematic sectional diagram showing another modification ofthe first embodiment of a method of manufacturing a light emittingdevice.

DETAILED DESCRIPTION OF EMBODIMENTS

Light emitting devices described below are intended to embody thetechnical concept of the present disclosure, and the present disclosureis not limited to or by what follows unless otherwise specified. Detailsdescribed in one embodiment or example are also applicable to otherembodiments and examples. Sizes, aspect ratios, positional relations andso on of members shown in the drawings may be exaggerated or omitted forclarifying or simplifying explanation.

First Embodiment

A method of manufacturing a light emitting device according to thisembodiment includes: providing a light-transmissive member having aplate-like shape (FIG. 1A); providing a plurality of light emittingelements each having a primary light emission surface and an electrodeformation surface on a side opposite to the primary light emissionsurface (FIG. 1B); bonding the light emitting elements to an uppersurface of a base member such that the electrode formation surfaces facethe upper surface of the base member (FIG. 1C); disposing the lightemitting elements on an upper surface of the light-transmissive membersuch that the primary light emission surface of each of the lightemitting elements faces the upper surface of the light-transmissivemember via a light-transmissive bonding member interposed therebetween(FIG. 1D); disposing a part of the bonding member on a lateral surfaceof the light emitting element (FIG. 1E); removing a part of thelight-transmissive member to form a groove between the light emittingelements (FIG. 1F); forming a light-reflective member in at least thegroove (FIG. 1G); and cutting the light-reflective member and the basemember (FIG. 1I-1).

In this embodiment, a plurality of light emitting elements are bonded toa light-transmissive member having a plate-like shape, thelight-reflective members are integrally formed, and the light-reflectivemembers and a base member are cut as described above. Accordingly, alight-transmissive member can be efficiently disposed on a lightemitting element and on the periphery thereof at an appropriate positionand in an appropriate shape.

Providing Light-Transmissive Member 11

As shown in FIG. 1A, the light-transmissive member 11 is obtained. Thelight-transmissive member 11 may have a plate-like shape such as a sheetshape or a film shape. The light-transmissive member 11 may have such asize that a plurality of light emitting elements 12 can be covered, inother words, a size larger than the total plane area of the primarylight emission surfaces 12 a of a plurality of light emitting elements12. The light-transmissive member 11 has a size of, for example, 20cm×10 cm, 3 cm×3 cm or 9 cm×6 cm. The surface of the light-transmissivemember 11 may be flat, or may have irregularities.

The light-transmissive member 11 may be one that can transmit lightemitted from the light emitting element 12, and is preferably one thattransmits, for example, at least 60%, at least 70%, or at least 80% ofthe light.

The light-transmissive member 11 can be formed from a light-transmissiveresin, glass, crystal or a sintered body of a fluorescent material, orthe like. The light-transmissive member 11 may be one including alight-transmissive member such as a light-transmissive resin or glasswhich contains a fluorescent material.

Examples of the light-transmissive resin include silicone resins,silicone modified resins, epoxy resins, phenol resins, polycarbonateresins, acryl resins, TPX resins, polynorbornene resins, and hybridresins including at least one of these resins. Among these examples,silicone resins and epoxy resins are preferable, and particularly,silicone resins is preferable due to its good light resistance and heatresistance.

Examples of the fluorescent material include those that are known in theart. Examples thereof include yttrium-aluminum-garnet (YAG)-basedfluorescent materials activated by cerium, lutetium-aluminum-garnet(LAG)-based fluorescent materials activated by cerium,nitrogen-containing calcium aluminosilicate (CAO-Al₂O₃—SiO₂)-basedfluorescent materials activated by europium and/or chromium, silicate((Sr, Ba)₂SiO₄)-based fluorescent materials activated by europium,@-sialon fluorescent materials, KSF-based fluorescent materials (K₂SiF₆:Mn), and fine particles of a semiconductor called a quantum dotfluorescent material or the like. Accordingly, a light emitting devicethat emits mixed-color light (e.g. white system) of primary light andsecondary light having a visible wavelength, or a light emitting devicethat is excited by primary light of ultraviolet light to emit secondarylight having a visible wavelength can be obtained. When the lightemitting device is used for a backlight of a liquid crystal display, orthe like, it is preferable to use a fluorescent material that is excitedby blue light emitted from the light emitting element 12 and emits redlight (e.g. KSF-based fluorescent material), and a fluorescent materialthat is excited by blue light emitted from the light emitting element 12and emits green light (e.g. ß-sialon fluorescent material). Accordingly,the color reproduction range of a display incorporating a light emittingdevice can be widened.

The shape of the fluorescent material may be of any of granular type,spherical type, hollow type, porous type and so on.

When the light-transmissive member contains the fluorescent material,the average particle size (i.e., median diameter) of the fluorescentmaterial is, for example, about 0.08 μm to 10 μm. Preferably, thefluorescent material is contained in an amount of 10% to 60% by weightbased on the weight of the light-transmissive member 11.

When an inorganic material such as glass or a fluorescent materialsintered body is used as the light-transmissive member 11, thelight-transmissive member is less likely to degraded, thereby realizinghigh reliable light emitting device. Such a light emitting device can beused as, for example, a light source for a headlight of a vehicle.

The light-transmissive member 11 may further contain a filler (e.g.diffusing agent, colorant or the like). Examples thereof include silica,titanium oxide, zirconium oxide, magnesium oxide, magnesium carbonate,magnesium hydroxide, calcium carbonate, calcium hydroxide, calciumsilicate, zinc oxide, barium titanate, aluminum oxide, iron oxide,chromium oxide, manganese oxide, glass and carbon black. Among theseexamples, titanium oxide is preferable because it relatively stable tomoisture etc., has a high refractive index, and is good in thermalconductivity. When the light-transmissive member is configured with amaterial containing a liquid resin and a particulate fluorescentmaterial, it is preferable to mix silica fine particles with thelight-transmissive member. Accordingly, thixotropy is imparted to amaterial of the light-transmissive member to reduce sedimentation of thefluorescent material, and thus it is possible to obtain alight-transmissive member in which a fluorescent material is uniformlydispersed. The shape of the particle of the filler may be of any ofgranular type, spherical type, hollow type, porous type and so on. Theaverage particle size (i.e. median diameter) is preferably about 0.08 μmto 10 μm. Accordingly, a light scattering effect can be obtained withhigh efficiency. Preferably, the filler is contained in an amount of 10%to 60% by weight in an amount of, for example, 10% to 60% by weightbased on the weight of the light-transmissive member. For example, if alayer containing a filler is provided on the light extraction surfaceside of the light-transmissive member, improvement of colornon-uniformity and reduction of stickiness of the light emitting devicecan be expected. When the light-transmissive member is formed using aresin, use of a filler having a high thermal conductivity can improvethermal conductivity to enhance the reliability of the light emittingdevice.

The light-transmissive member 11 may have a single layer, or have alayered structure with a plurality of layers as described later.

The thickness of the light-transmissive member 11 affects the height ofthe light-emitting device. When the thickness of the light-transmissivemember 11 decreases, the risk of breakage is increased, and the amountof a fluorescent material that can be contained is limited. Therefore,the thickness of the light-transmissive member 11 is, for example, 10 μmto 300 μm, preferably 30 μm to 200 μm.

The light-transmissive member 11 may be formed using a material in whicha liquid resin and, as necessary, a fluorescent material, by, forexample, compression molding, transfer molding, injection molding,spraying, printing, potting or the like. Alternatively, a fluorescentmaterial formed in a substantially uniform thickness by electrophoreticdeposition or the like can be impregnated with a resin to form thelight-transmissive member 11.

Providing Light Emitting Element 12

As shown in FIG. 1B, the light emitting element 12 has the primary lightemission surface 12 a, and an electrode formation surface 12 b with anelectrode disposed on a side opposite to the primary light emissionsurface 12 a.

The size, shape, emission wavelength and the like of the light emittingelement 12 can be appropriately selected. The sizes, shapes, emissionwavelengths and the like of a plurality of light emitting elements 12may be different from each other, but are preferably the same.

In the light emitting element 12, a first semiconductor layer (e.g.n-type semiconductor layer), a light emitting layer, and a secondsemiconductor layer (e.g. p-type semiconductor layer) are stacked inthis order as a semiconductor layered body, and both a first electrodeelectrically connected to the first semiconductor layer and a secondelectrode electrically connected to the second semiconductor layer areprovided on the same surface side (e.g. second semiconductor layer-sidesurface). Accordingly, flip-chip mounting can be performed in which thelight emitting element is bonded oppositely to the base member 13. Thesemiconductor layered body is normally stacked on a growth substrate,and the light emitting element 12 may include a growth substrate, or mayinclude no growth substrate. The types and materials of the firstsemiconductor layer, the light emitting layer, and the secondsemiconductor layer are not particularly limited, and examples thereofinclude various semiconductors such as Group III-V compoundsemiconductors and Group II-VI compound semiconductors. Specificexamples thereof include nitride-based semiconductor materials such asIn_(X)Al_(Y)Ga_(1-X-Y)N (0≤X, 0≤Y, X+Y≤1). Each of the thickness and thelayer structure of each layer can be set to one that is known in theart.

The shape of the semiconductor layered body in plan view is preferably aquadrangle or a shape similar to a quadrangle, but is not particularlylimited. The size of the semiconductor layered body in plan view can beappropriately adjusted in accordance with the size of the light emittingelement 12 in plan view. For example, the semiconductor layered body,that is, the length of the light emitting element 12 has a length of 200μm to 1500 μm in a longitudinal direction, a length of 50 μm to 400 μmin a width direction, and a thickness of the 80 μm to 200 μm.

The first electrode and the second electrode can be formed from, forexample, a single-layer film or layered film of metals such as Au, Pt,Pd, Rh, Ni, W, Mo, Cr and Ti, or alloys thereof. Specifically, mentionis made of layered films such as those of Ti/Rh/Au, W/Pt/Au, Rh/Pt/Au,W/Pt/Au, Ni/Pt/Au and Ti/Rh, in order from the semiconductor layer side.As the thickness of the film, a thickness of any of films that are usedin the art may be employed. Preferably, a material layer, of whichreflectivity to light emitted from the light emitting layer is higherthan that of each of other materials of the electrode, is disposed oneach of a side close to the first semiconductor layer and a side closeto the second semiconductor layer. Examples of the material having ahigh reflectivity include layers containing silver, a silver alloy oraluminum. When silver or a silver alloy is used, it is preferable toform a covering layer that covers the surface (i.e., upper surface andend surface) of the layer for mitigating migration of silver. Normally,such a covering layer may be one formed of a metal or alloy that is usedas an electrically conductive material, and the covering layer is, forexample, a single layer or stacked layer containing a metal such asaluminum, copper or nickel.

In the light emitting element 12, a DBR (i.e., distributed Braggreflector) layer or the like may be disposed on electrode formationsurface side of the semiconductor layered body to the extent nothindering electrical connection. For example, the DBR has a multilayerstructure in which a low-refractive-index layer and ahigh-refractive-index layer are stacked on a base layer composed anoxidized film or the like, as appropriate, and the DBR reflectsselectively reflects light having a predetermined wavelength.Specifically, films having various refractive indices and thicknesseswhich are to reflect a quarter of wavelength, are alternately layered,thereby enabling reflection at the predetermined wavelength in a highlyefficient manner. The DBR can be formed using as a material an oxide ornitride of at least one selected from the group consisting of Si, Ti,Zr, Nb, Ta and Al.

Bonding Light Emitting Element 12

As shown in FIG. 1C, a plurality of light emitting elements 12 is bondedto the upper surface of the base member 13 so as to face the electrodeformation surfaces 12 b to the upper surface of the base member 13.Preferably, a plurality of light emitting elements 12 is regularlyarranged, and a plurality of light emitting elements 12 is provided atsubstantially equal intervals. Accordingly, cutting as described latercan be easily controlled.

For example, the interval between light emitting elements 12 may be 10μm to 1000 μm, and is preferably, for example, 200 μm to 800 μm.Accordingly, the material costs of the later-describedlight-transmissive bonding member 14 and/or light-reflective member 16,etc. can be reduced.

The base member 13 used here may be a base member to be used only forarranging light emitting elements 12 at equal intervals, or a mountingsubstrate with positive and negative terminals disposed on a surfacethereof. In the former case, the base member may be removed, for exampleafter a light emitting device is manufactured by a series of steps. Inthe latter case, it is preferable to connect the electrodes of the lightemitting element 12 to positive and negative terminals, respectively, byan electrically conductive bonding member.

The base member 13 is, for example, one formed using a resin film, ametal plate, a ceramic plate or the like alone, or a composite thereof.The base member 13 may be rigid, or may have flexibility.

Arranging Light Emitting Elements 12 and Bonding Member 14 onLight-Transmissive Member 11

As shown in FIG. 1D, a plurality of light emitting elements 12 isdisposed on the upper surface of the light-transmissive member 11 suchthat the primary light emission surfaces 12 a of a plurality of lightemitting elements 12 face the upper surface of the light-transmissivemember 11 with the light-transmissive bonding member 14 interposedtherebetween.

The light-transmissive bonding member 14 to be used for bonding thelight emitting elements 12 to the light-transmissive member 11 ispreferably one that transmits 60% or more of light emitted from thelight emitting element. The bonding member 14 is preferably a liquidmaterial capable of being cured by light, heat or the like. Inparticular, a thermosetting resin such as a silicone resin, a siliconemodified resin, an epoxy resin or a phenol resin is preferably used asthe bonding member 14. The bonding member 14 may contain an additivethat scatters light. Accordingly, light emitted from the light emittingelement can be made uniform in the bonding member 14.

For example, as shown in FIG. 2, the light-transmissive bonding member14 can be used with the bonding member 14 disposed on the upper surfaceof the light-transmissive member 11 in providing the plate-like shapedlight-transmissive member 11. As described later, the bonding member 14may be disposed on the primary light emission surfaces 12 a of the lightemitting elements 12 beforehand.

The amount of the bonding member 14 is required to be sufficient forbonding the light emitting elements 12 to the light-transmissive member11, and is preferably such that a part or the whole of the lateralsurfaces 12 c of the light emitting elements 12 can be covered. Further,the amount of the bonding member 14 is more preferably such that thewhole of the lateral surfaces 12 c of the light emitting elements 12 canbe covered.

In particular, it is preferable that the bonding member 14 is disposedin such a sufficient amount that the bonding member 14 existscontinuously among adjacent ones of the light emitting elements 12 asshown in FIG. 1E, in other words, the lateral surface of one of thelight emitting elements 12 is connected to the lateral surface ofadjacent one of the light emitting elements 12 by the bonding member 14.Accordingly, light emitted from a plurality of light emitting elements12 can be made uniform in the bonding member 14, so that light emittedfrom the light emitting device is less likely to be non-uniform.

To continuously dispose the bonding member 14 among a plurality ofadjacent light emitting elements 12, for example, it is preferable toapply a pressure in a direction indicated by the arrow in FIG. 1E, orapply a pressure from the light-transmissive member side. The pressurehere is, for example, 1.0 Kg to 2.5 Kg. Further, it is more preferableto apply heat, light or the like to the bonding member 14 in order tocure the bonding member 14 after application of a pressure. Accordingly,the light emitting elements 12 and the light-transmissive member 11 canbe fixed firmly at an appropriate position. The temperature of heatapplied in this fixation is preferably at 300° C. at most, and morepreferably at in a range of from 150° C. to 200° C.

Preferably, the bonding member 14 is disposed in such a manner that athickness (as measured along a direction parallel to the lateral surface12 c) of a portion in which the bonding member 14 is in contact with thelateral surface 12 c of the light emitting elements 12 between lightemitting elements 12 is greater than a thickness of a portion in whichthe bonding member 14 is away from the lateral surface 12 c of the lightemitting element 12 as shown in, for example, FIG. 1E. In other words,the bonding member 14 is preferably disposed in such a manner that theouter surface of the bonding member 14 forms a recess inwardly curvedtoward the light-transmissive member 11 side between light emittingelements 12. At the time of cutting light emitting elements 12 from eachother, the outer surface of the bonding member 14 disposed on thelateral surface 12 c of the light emitting element 12 can be inclined soas to extend toward the cut surface. Accordingly, light emitted from thelateral surface 12 c of the light emitting element 12 can be moreefficiently extracted to the light-transmissive member 11.

Preferably, the bonding member 14 covers the lateral surface of thelight emitting element 12 as large area as possible. The bonding membercovers at least 50%, preferably at least 70%, more preferably at least90% of the lateral surface of the light emitting element 12.Accordingly, light emitted from the lateral surface 12 c of the lightemitting element 12 can be more efficiently extracted to thelight-transmissive member 11.

Forming Groove 15

As shown in FIG. 1F, a part of the light-transmissive member 11 isremoved to form the groove 15 between light emitting elements 12. Forexample, the width of the groove 15 formed by removing thelight-transmissive member 11 is preferably smaller than a distancebetween light emitting elements 12, more preferably a such a width thatthe light-transmissive member 11 having a width of 100 μm or more fromthe lateral surface 12 c of the light emitting element 12 remains.Specifically, the width of the groove 15 is 5 μm to 10 μm. The width ofthe groove 15 is preferably constant in the depth direction, but maygradually or sharply increase or decrease in the depth direction.

The groove 15 is preferably formed with such a depth that the whole ofthe light-transmissive member 11 is removed in the thickness direction,and it is more preferable that the whole of the light-transmissivebonding member 14 is removed in the thickness direction to form anopening that passes through the light-transmissive member 11 and thebonding member 14 as shown in FIG. 1F. It is preferable that the groove15 is formed at a central part between light emitting elements 12, andtherefore it is more preferable that a portion of the light-transmissivebonding member 14, which has the smallest thickness, is removed in thetotal thickness. Specifically, the depth of the groove 15 is in a rangeof from 150 μm to 210 μm.

When such a groove 15 is formed, the later-described light-reflectivemember 16 can be easily formed on the periphery of the light emittingelement 12 and between the light emitting element 12 and the base member13. Further, by adjusting the width of the groove 15, the thickness ofthe light-transmissive bonding member 14 that covers the lateral surface12 c of the light emitting element 12 can be appropriately set, so thatlight emitted from the light emitting element 12 can be made uniform inthe bonding member 14, or reflection or scattering of light can becontrolled.

The groove 15 can be formed by partial polishing or grinding, cutting,processing by Thomson blade, ultrasonic processing, laser processing,dicing using a blade having a V-shaped edge, or the like.

Forming Light-Reflective Member 16

As shown in FIG. 1G, the light-reflective member 16 is formed at leastin the groove 15. The light-reflective member 16 is preferably formed soas to cover the whole inner wall of the groove 15, and more preferably,the light-reflective member 16 is formed so as to cover a part or thewhole of the periphery of the light emitting element 12 and a gapbetween the light emitting element 12 and the base member 13.Accordingly, light emitted from the primary light emission surface 12 aof the light emitting element 12 can be efficiently extracted from theupper side of the light-transmissive member 14 through the inside of thelight-transmissive member. By filling the whole of the inside of thegroove 15 with the light-reflective member 16, the lateral surface ofthe light-transmissive member 11 is covered with the light-reflectivemember 16. Accordingly, it is possible to obtain a light emitting devicehaving a high contrast between a light emitting region and anon-light-emitting region, and distinguishability therebetween.

Preferably, the light-reflective member 16 is formed using a materialcapable of reflecting light emitted from the light emitting element 12.Specifically, the light-reflective member 16 can be formed by adding alight-reflective substance in a resin material same as or similar to theabove-described light-transmissive resin. Examples of thelight-reflective substance include titanium oxide, silicon oxide,zirconium oxide, magnesium oxide, yttrium oxide, yttria-stabilizedzirconia, calcium carbonate, calcium hydroxide, calcium silicate, zincoxide, barium titanate, potassium titanate, alumina, aluminum nitride,boron nitride and mullite. In particular, titanium oxide is preferablebecause it is relatively stable to moisture etc., and has a highrefractive index.

The light-reflective member 16 can be formed by molding such ascompression molding, transfer molding or injection molding, printing,potting or the like. In particular, compression molding or transfermolding is preferable because it is more easily carried out.

Preferably, the light-reflective member 16 is formed so as to be flushwith the upper surface of the light-transmissive member 11 bonded to theprimary light emission surface 12 a of each of the light emittingelements 12. Accordingly, it is possible to produce a light emittingdevice that is thin, and has distinguishability between a light emittingregion and a non-light-emitting region.

Cutting

As shown in FIG. 1H, the light-reflective member 16 and the base member13 are cut. Accordingly, a plurality of light emitting devices can beobtained. Cutting may be performed every one light emitting element, ormay be performed every two or more light emitting elements 12 12 betweenlight emitting elements 12. In the latter case, a light emitting deviceincluding a plurality of light emitting elements 12 can be obtained.

Cutting can be performed by a method such as dicing, processing byThomson blade, ultrasonic processing or laser processing.

Cutting may be performed between adjacent light-transmissive members 11so as to remove the light-reflective member corresponding to a gapbetween the adjacent light-transmissive members 11. Preferably, cuttingis performed between adjacent light-transmissive members 11 by removingthe light-reflective member with a width smaller than a gap betweenlight-transmissive members 11 so that the light-reflective member coversthe lateral surfaces of the light-transmissive member 11. Accordingly,emission of light from the lateral surface of the light-transmissivemember 11 can be prevented to obtain a light emitting device havingparting property.

The base member 13 may be removed after forming the light-reflectivemember 16 or after cutting. When the base member 13 is removed afterforming the light-reflective member 16, only the light-reflective member16 may be cut.

Light Emitting Device

In the light emitting device produced by the above-describedmanufacturing method, the lateral surfaces of the light-transmissivemember and the outer surfaces of the bonding member are covered with thelight-reflective member as shown in FIG. 1I. The outer surface of thebonding member is inclined so as to extend toward the light-transmissivemember. Accordingly, light emitted from the lateral surface 12 c of thelight emitting element 12 can be efficiently extracted to thelight-transmissive member 11, and it is possible to obtain a lightemitting device having a high contrast between a light emitting regionand a non-light-emitting region, and distinguishability therebetween.Further, a part of the bonding member between light emitting elements,and the whole of the bonding member in the thickness direction areremoved during formation of the groove, thus the lateral surface of thelight-transmissive member is flush with a part of the outer surface ofthe bonding member. Accordingly, a light emitting device having a smallsize can be obtained.

Modification

In the step of forming the groove 15, a position at which the groove 15is formed may be selected as necessary. The groove 15 may be formedbetween each one of the light emitting elements 12 as shown in, forexample, FIG. 1F, or may be formed every other light emitting element12, or may be formed every two or more light emitting elements 12.

When the groove 15 is formed between light emitting elements 12, andcutting is performed every two or more light emitting elements 12, it ispossible to obtain a light emitting device, in which a plurality oflight emitting elements 12 are included, having distinguishabilitybetween light emitting elements 12 as shown in FIG. 6A. Accordingly, itis possible to obtain a light emitting device having a high contrastbetween a light emitting region and a non-light-emitting region, andgood distinguishability therebetween.

The groove 15 may be formed only between light emitting elements 12 tobe cut. When the light-reflective member 16 is formed in the groove 15,and cutting is performed between light emitting elements 12 where thegroove 15 is formed, it is possible to obtain a light emitting device,in which a plurality of light emitting elements 12 are included andbonding members and light-transmissive members are connected betweenlight emitting elements as shown in FIG. 6B.

Bonding members 14 that bond light emitting elements 12 may beconnected, or may be separated from one another. Preferably, the bondingmember 14 is situated so as to connect light emitting elements 12 asshown in FIG. 6B. This structure allows light from the light emittingelement 12 to be also guided to the light-transmissive member throughthe bonding member from a gap between light emitting elements 12, andtherefore luminance unevenness of the light emitting device can bereduced.

Second Embodiment

A method of manufacturing a light emitting device according to thisembodiment includes providing a light-transmissive member 21 having alayered structure instead of providing the light-transmissive member 11having a single-layer structure.

For example, the light-transmissive member 21 may be a layered bodystructured by a fluorescent material-containing layer 21 b containing afluorescent material and a fluorescent material-free layer 21 a whichdoes not contain a fluorescent material. Alternatively, thelight-transmissive member 21 may be a layered body in which three ormore layers thereof are alternately stacked. The light-transmissivemember 21 may have a structure in which a plurality of fluorescentmaterial-containing layers each containing different kinds offluorescent materials is stacked, or a structure in which a fluorescentmaterial-free layer is further stacked on the above-mentionedfluorescent material-containing layers. For example, a layer containinga fluorescent material that emits green light and a layer containing afluorescent material that emits red light may be formed separately, andjoined together to obtain a light-transmissive member having two-layerstructure. The fluorescent material-containing layer 21 b or thefluorescent material-free layer 21 a may be formed, followed by formingthe fluorescent material-containing layer 21 b and/or the fluorescentmaterial-free layer 21 a on the upper surface thereof by a sprayingmethod or the like to obtain a light-transmissive member having astructure with two or more layers.

With the light-transmissive member 21 having such a two-layer structure,when the fluorescent material-containing layer 21 b contains afluorescent vulnerable to moisture and/or an external environment, e.g.a KSF fluorescent material, it is preferable to dispose the fluorescentmaterial-free layer 21 a on a side far from the primary light emissionsurface of the light emitting element. Thus, in providing thelight-transmissive member, the light-transmissive member 11 ispreferably disposed on one surface of the fluorescentmaterial-containing layer 21 b of the light-transmissive member 21 asshown in FIG. 3.

Accordingly, a fluorescent material vulnerable to moisture etc. isprotected by the fluorescent material-free layer 21 a, in other words,the fluorescent material is less likely to be exposed to an externalenvironment, so that degradation of the fluorescent material can bemitigated.

When the light-transmissive member contains a fluorescentmaterial-containing layer and a fluorescent material-free layer 11 a,for example, the thickness of the fluorescent material-containing layeris in a range of from 10 μm to 250 μm, preferably in a range of from 30μm to 200 μm.

Except for the above, the manufacturing method is essentially the sameas or a similar to in the first embodiment, and has the same as or asimilar effect as in the first embodiment 1.

When the light-transmissive member 21 is used, a bonding member 14 maybe disposed on a primary light emission surface 12 a of a light emittingelement 12 beforehand as described later, instead of disposing thebonding member 14 on the light-transmissive member 21.

Third Embodiment

A method of manufacturing a light emitting device according to thisembodiment includes disposing a bonding member 14 on a primary lightemission surface 12 a of a light emitting element 12 beforehand as shownin FIG. 4, instead of disposing a bonding member on the upper surfacesof light-transmissive members 11 and 21 beforehand.

Disposition of the bonding member 14 on the primary light emissionsurface 12 a of the light emitting element 12 is preferably performedafter boding the light emitting element 12 to the upper surface of abase member 13.

For example, manufacturing the light emitting device according to thisembodiment can be accomplished by a method as follows. A plurality oflight emitting elements 12 is bonded to the base member 13 as shown inFIG. 4A. The bonding member 14 is disposed on a flat base 17 as shown inFIG. 4B. The light emitting elements 12 bonded to the base member 13 isbrought into contact with the bonding member 14 disposed on the flatbase 17 as shown in FIG. 4C. Then the bonding member can be disposed onthe primary light emission surfaces 12 a of the light emitting elements12 as shown in FIG. 4D.

Accordingly, the bonding member 14 can be collectively and uniformlydisposed on the light emitting elements 12 in an appropriate amount. Atthe time of bringing the light emitting elements 12 into contact withthe bonding member 14, heat may be applied by the bonding member 14 thatis used. Alternatively, the bonding member 14 may be disposed on theprimary light emission surfaces 12 a of light emitting elements 12 usinga technique such as pin transfer, dispensing or printing.

Except for the above, the manufacturing method is essentially the sameor a similar as in the first embodiment, and has the same or a similareffect as in the first embodiment 1.

Fourth Embodiment

A method of manufacturing a light emitting device according to thisembodiment includes forming a light-reflective member 16 such that aplurality of light emitting elements 12 and a light-transmissive member11 are wholly embedded as shown in FIG. 5A, in other words, the uppersurface of the light-transmissive member 11 is covered.

Thereafter, a light-reflective member 16 disposed on the upper surfaceof the light-transmissive member 11 may be removed to expose thelight-transmissive member 11 so that the light-reflective member 16 isflush with the upper surface of the light-transmissive member 11 asshown in FIG. 5B.

The light-reflective member 16 can be removed by polishing or grinding,cutting, polishing, CMP, ultrasonic processing, laser processing or thelike.

Here, in particular, the light-transmissive member 21 having a two-layerstructure with a fluorescent material-containing layer 21 b and afluorescent material-free layer 21 a can be used, and the fluorescentmaterial-free layer 21 a can be disposed on a side far from the primarylight emission surface of the light emitting element. In this case, theamount of a fluorescent material in the light-transmissive member 21 isless likely to be changed even if a part of the light-transmissivemember 21 is removed together with the light-reflective member 16. Thus,stable light conversion can be attained.

Except for the above, the manufacturing method is essentially the sameas or a similar to that in the first embodiment, and has the same or asimilar effect as in the first embodiment 1.

What is claimed is:
 1. A method of manufacturing a light emittingdevice, the method comprising: providing a light-transmissive memberhaving a plate-like shape; providing a plurality of light emittingelements each having a primary light emission surface and an electrodeformation surface on a side opposite to the primary light emissionsurface; bonding the light emitting elements to an upper surface of abase member such that the electrode formation surface of each of thelight emitting elements faces the upper surface of the base member;disposing a generally flat layer of a light-transmissive bonding memberon an upper surface of the light-transmissive member; disposing thelight emitting elements on the upper surface of the light-transmissivemember such that the primary light emission surface of each of the lightemitting elements faces the upper surface of the light-transmissivemember via the bonding member interposed therebetween; disposing a partof the bonding member on a lateral surface of each of the light emittingelements; removing a part of the light-transmissive member to form agroove between the light emitting elements; forming a light-reflectivemember at least in the groove; and cutting the light-reflective member.2. The method of manufacturing a light emitting device according toclaim 1, wherein the disposing of the part of the bonding member on thelateral surface of each of the light emitting elements includesdisposing the bonding member such that a thickness of a portion of thebonding member which is in contact with the lateral surface of acorresponding one of the light emitting elements is greater than athickness of a portion of the bonding member which is away from thelateral surface of the corresponding one of the light emitting elements,the thickness being measured along a direction parallel to the lateralsurface of the corresponding one of the light emitting elements.
 3. Themethod of manufacturing a light emitting device according to claim 1,wherein the providing of the light-transmissive member includesproviding a layered body of a fluorescent material-containing layer anda fluorescent material-free layer as the light-transmissive member, andthe disposing of the light emitting elements on the upper surface of thelight-transmissive member includes disposing the light emitting elementson the fluorescent material-containing layer such that the primary lightemission surface of each of the light emitting elements faces thefluorescent material-containing layer.
 4. The method of manufacturing alight emitting device according to claim 1, wherein the disposing of thepart of the bonding member on the lateral surface of each of the lightemitting elements includes disposing the part of the bonding member tocontact both of the lateral surface of one of the light emittingelements and the lateral surface of an adjacent one of the lightemitting elements facing each other.
 5. The method of manufacturing alight emitting device according to claim 1, wherein the removing of thepart of the light-transmissive member to form the groove between thelight emitting elements includes removing a part of the bonding member.6. The method of manufacturing a light emitting device according toclaim 1, wherein the forming of the light-reflective member includes:covering the upper surface of the light-transmissive member; andexposing the light-transmissive member by removing the light-reflectivemember disposed on the upper surface of the light-transmissive member.7. The method of manufacturing a light emitting device according toclaim 1, further comprising cutting the base member after the forming ofthe light-reflective member or after the cutting of the light-reflectivemember.
 8. The method of manufacturing a light emitting device accordingto claim 1, wherein the removing of the part of the light-transmissivemember includes adjusting a width of the groove so that a portion of thelight-reflective member covering the lateral surface of each of thelight emitting elements has a prescribed thickness.
 9. The method ofmanufacturing a light emitting device according to claim 1, wherein theproviding of the plurality of light emitting elements includes forming adistributed Bragg reflector on an electrode formation surface side of asemiconductor layered body of each of the light emitting elements. 10.The method of manufacturing a light emitting device according to claim1, wherein the bonding of the light emitting elements to the uppersurface of the base member includes arranging the light emittingelements at an interval of 10 μm to 1000 μm.
 11. The method ofmanufacturing a light emitting device according to claim 1, wherein thebonding member contains an additive that scatters light.
 12. The methodof manufacturing a light emitting device according to claim 1, whereinthe disposing of the part of the bonding member on the lateral surfaceof each of the light emitting elements includes disposing the part ofthe bonding member so that the bonding member covers at least 50% of thelateral surface of each of the light emitting elements.
 13. The methodof manufacturing a light emitting device according to claim 1, whereinthe removing of the part of the light-transmissive member includesadjusting a depth of the groove to be in a range of from 150 μm to 210μm.
 14. The method of manufacturing a light emitting device according toclaim 1, wherein the disposing of the part of the bonding member on thelateral surface of each of the light emitting elements includesdisposing of the part of the bonding member so that an outer surface ofthe part of the bonding member is inclined so as to extend away from thelateral surface of each of the light emitting elements.
 15. The methodof manufacturing a light emitting device according to claim 1, whereinthe forming of the light-reflective member includes forming thelight-reflective member so that a surface of the light-reflective memberis flush with a surface of the light transmissive member.
 16. The methodof manufacturing a light emitting device according to claim 1, whereinthe removing of the part of the light-transmissive member includesforming the groove between every two or more light emitting elements.17. The method of manufacturing a light emitting device according toclaim 3, wherein the providing of the light-transmissive member includesproviding the fluorescent material-containing layer on a side closer tothe primary light emission surface of each of the light emittingelements, and providing the fluorescent material-free layer on a sideaway from the primary light emission surface of each of the lightemitting elements.
 18. The method of manufacturing a light emittingdevice according to claim 1, further comprising bringing the lightemitting elements into contact with the bonding member and applying heatwhile the light emitting elements are in contact with the bondingmember.
 19. The method of manufacturing a light emitting deviceaccording to claim 1, wherein the disposing of the light emittingelements on the upper surface of the light-transmissive member includesapplying a pressure so that the primary light emission surface of eachof the light emitting elements get closer to the upper surface of thelight-transmissive member, and curing the bonding member by heat orlight after the applying of the pressure.
 20. The method ofmanufacturing a light emitting device according to claim 12, wherein thedisposing of the part of the bonding member on the lateral surface ofeach of the light emitting elements includes disposing the part of thebonding member so that the part of the bonding member covers an entiretyof the lateral surface of each of the light emitting elements.